1. Field of Invention
The invention relates to material hardness testers which convert, or afford readings to convert, the displacement of a penetrator into the material being tested into a hardness indication such as a number on a Brinell Scale or the like.
2. Description of Prior Art
Available portable hardness testers may be typically characterized as mechanical devices having penetrators mechanically coupled to dial indicators or the like for furnishing a correlation between a depth of penetration of the penetrator into the material being tested and the hardness of the material, or furnishing displacement readings enabling the user to compute such hardness. Portable hardness testers in common use require careful cleaning and polishing of the surface of the material being tested in order to obtain useful hardness readings, and even with such surface preparation the testers lack accuracy and dependable repeatability, and are subject to malfunctioning due to high or low temperatures and wear of critical parts.